Broadcasters, such as television and radio broadcasters, have taken steps forward to provide an audience with digital supplementary services, such as program information, news, weather information, competitions and other related contents, in addition to a traditional media stream. The digital supplementary services are usually delivered to the audience over the Internet using the audience's personal computers or other media devices capable of connecting to the Internet.
The audience is provided with more mobility by media devices of cellular telecommunication systems, which media devices are equipped with a receiver, such as an FM radio, for receiving media streams broadcast by broadcasters. Broadcasters typically provide Internet services, which can be accessed by media devices, such as one equipped with a WAP (Wireless Application Protocol), capable of connecting to such a service.
Typically, the frequency used to transmit a broadcast media stream varies, depending on a geographical location. Each broadcast transmitter has a given coverage area, and transmitters serving adjacent areas use different frequencies. Thus, the same broadcast media stream is transmitted on a predetermined number of frequencies, and these frequencies may be called parallel frequencies.
When a user of a media device tuned to a given broadcast stream travels from one geographical area to another, the quality of reception of the broadcast media stream deteriorates gradually as the distance between the broadcast transmitter and the media device increases.
A media device cannot automatically swap to a parallel frequency transmitting the media stream on a new location without information about the frequency. Thus, in the worst case, the broadcast media stream fades away while a supplementary service is still being delivered to the media device.
In prior art, some solutions have been presented to overcome this problem. One solution is to utilize RDS (The Radio Data System). In RDS, supplementary information is attached to the broadcast media stream. The supplementary RDS information comprises identification of the station or the media stream. Thus, the receiver is able to distinguish media streams from each other automatically. However, this requires that the receiver should be RDS compliant, i.e. equipped with suitable features to receive RDS transmission. Furthermore, the receiver must scan the available frequency range in order to detect a parallel frequency of the media stream currently being received.
Publication US 2004/0198217 discloses a follow-me broadcast reception system (FBRS). The document discloses a solution where a FBRS server maintains a history of a mobile user's location and the frequency to which the user's broadcast receiver was tuned. The solution utilizes this history information to resolve a parallel frequency. A drawback of this solution is the need to determine and store the location of the mobile user, and the need for a continuous connection between a server and a mobile user.